Remember, security against cracking is a combination of password strength and key derivation function strength . Nothing will save you if your password is "password". Not much will save you if your password is hashed with MD5. But scrypt can be over 100,000,000 time stronger than MD5 -- so if you're using scrypt you can afford to use a password which is 100,000,000 times weaker. "jdtwbv" hashed using scrypt is strong…
Just use bcrypt :-p
A Really Good Article on How Easy it Is to Crack Passwords
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Re: A Really Good Article on How Easy it Is to Crack Passwords
#12Passwords are broken and I really wish we would all move away from them. Persona is a nice idea with regards to privacy and control, but it's still a password that you need to remember, which can be cracked. Also, people generally don't use strong passwords. What irks me is that every OS in use today has support for strong cryptography and browser vendors could easily integrate that. We would no longer register for a…
And how do you access your identity from a device that isn't your own?
I'm 100% with you, it would be a major step forward - but it's too inflexible for Joe & Jane.
Re: A Really Good Article on How Easy it Is to Crack Passwords
#13Earlier quoted context omitted.
Just use bcrypt :-p
bcrypt is not bad and you're definitely better off with that than with MD5, but scrypt performs better for these sort of things. There was an article on HN a week or so ago about this.
One of the problems of scrypt is a lack of language bindings. There's no officially blessed language binding for PHP, there's a ruby gem that only works on MRI but doesn't support jruby. Bcrypt on the other hand is widely supported, simple and easy to use implementations exist for devise and activerecord for example. I'd pick the slightly worse but widely supported algorithm and rather tune the work factor than being stuck with an extension that might or might not be supported depending on the authors availability of time and resources.
This all can change, but that's the current state of things. Sorry scrypt.
Re: A Really Good Article on How Easy it Is to Crack Passwords
#14Earlier quoted context omitted.
Just use bcrypt :-p
http://www.unlimitednovelty.com/2012/03/dont-use-bcrypt.html
Great article. Old discussion here
Re: A Really Good Article on How Easy it Is to Crack Passwords
#15Remember, security against cracking is a combination of password strength and key derivation function strength . Nothing will save you if your password is "password". Not much will save you if your password is hashed with MD5. But scrypt can be over 100,000,000 time stronger than MD5 -- so if you're using scrypt you can afford to use a password which is 100,000,000 times weaker. "jdtwbv" hashed using scrypt is strong…
> "jdtwbv" hashed using scrypt is stronger than "H.W8Jz&r3" hashed using MD5*
But "password" is still grossly insecure in either case, it'll still be the first thing that someone performing a dictionary attack will try. Never tell people how good your key derivation function is, lest they misunderstand and think it means they don't have to chose a non-obvious password/passphrase.
Re: A Really Good Article on How Easy it Is to Crack Passwords
#16> "This is an answer to the batteryhorsestaple thing." Steube misunderstands the xkcd comic [1]. There's a really good comment which explains it: "It could be argued that Randall's example of 4 words is too short -- and indeed, for some applications, it is. However for a typical dictionary size, and genuinely random selection, it is massively stronger than "typical" passwords and in fact easily adequte to defeat the…
What makes you think he misunderstands it? For the cracker it's not about entropy per se, it's a game to come up with algorithms that crack more passwords for less compute power. The XKCD comic got a lot of mindshare so it makes sense to target algorithms towards that type of password.
I think Schneier's suggestion of reducing it to the first letter of each word is vastly preferable because it packs the majority of entropy from random word selection into the least amount of typing.
Re: A Really Good Article on How Easy it Is to Crack Passwords
#17Why not force the user to have strong login credentials?
I'm creating an online system that will store users' sensitive financial data. When setting up an account, the user will have to choose a password as normal, but will also be given a passphrase of the form "correct horse battery staple" that they must write down. To log in, the user will need to enter (a) username; (b) password; and (c) passphrase.
It is effectively a poor man's two-factor authentication - the second factor being the piece of paper containing the passphrase. I think it strikes a good balance between security, convenience and cost.
What do others think of this approach?
Re: A Really Good Article on How Easy it Is to Crack Passwords
#18Passwords are broken and I really wish we would all move away from them. Persona is a nice idea with regards to privacy and control, but it's still a password that you need to remember, which can be cracked. Also, people generally don't use strong passwords. What irks me is that every OS in use today has support for strong cryptography and browser vendors could easily integrate that. We would no longer register for a…
And how do you access your identity from a device that isn't your own? I'm 100% with you, it would be a major step forward - but it's too inflexible for Joe & Jane.
and also it kinda destroys the ubiquity of the service. you have to admit, the ability to access your account from any device anywhere is pretty cool (and very critical in some cases)
Re: A Really Good Article on How Easy it Is to Crack Passwords
#19Why not force the user to have strong login credentials? I'm creating an online system that will store users' sensitive financial data. When setting up an account, the user will have to choose a password as normal, but will also be given a passphrase of the form "correct horse battery staple" that they must write down . To log in, the user will need to enter (a) username; (b) password; and (c) passphrase. It is effec…
It's certainly better than just a password, and as you say is a nice balance between usability and strong passwords.
However, I'd be careful about thinking of it as any sort of 2-factor authentication and wouldn't bestow any of the advantages of 2-factor auth on your scheme.
A static secret, no matter how complex, doesn't really prove ownership because multiple people can trivially have a copy of the secret at the same time. So you don't have a knowledge and a physical factor, just a convoluted knowledge factor.
Better than just a password, but don't let it g e you a false sense of security.
Re: A Really Good Article on How Easy it Is to Crack Passwords
#20Why not force the user to have strong login credentials? I'm creating an online system that will store users' sensitive financial data. When setting up an account, the user will have to choose a password as normal, but will also be given a passphrase of the form "correct horse battery staple" that they must write down . To log in, the user will need to enter (a) username; (b) password; and (c) passphrase. It is effec…
The passphrase looks to be very weak if it is just something like 4 english words. And fails on the convenience test.